Vertical Axis Wind Turbines have been in use for a very long time, new technology and materials have played a big part to overcome the deficiencies and improve torque output from VAWT but work to improve the output torque is continuing and heading in the right direction.
Some previous patent citations are mentioned below:
US20030161729 Hank LindhornWO2004079186A2Robert D HuntWO2004109097A1Willi HenkenhafWO2012007630A1Andreu J M JuanWO2005100782A1John Edward MullengerWO2007129049A1David McsherryEP1096144A2Miyake Kazuya
This Self-directed Vertical Axis Wind Turbine is capable of holding its blade angle in a positively controlled and pre calculated angle while rotating against the in-coming wind to produce the optimum power relative to wind speed resulting in additional torque output compared to other similar size of vertical axis wind turbines.